Pulse Wave Transmission And Reflection In The Detection Of Atherosclerosis

Atherosclerosis which occurs in the large and medium sized arteries has a high incidence of human arterial disease and is a major cause of heart disease and stroke. The number of deaths due to cardiovascular disease is in the first place of that of total human deaths. To better understand the impact of human arteriosclerosis, and develop apparatus which can detect atherosclerosis in the early time, it is necessary to have a research on cardiovascular hemodynamics. One very important aspect is the study of the pulse wave.Pulse waves as a phenomenon of human physiology, have always been of concern. In traditional Chinese medicine, doctors use the radial arterial pulse diagnosing disease. In the west, pulse wave has also carried out a lot of research. Pulse wave in this article means the periodic fluctuate of arterial blood pressure and flow which is accompany with the systolic and diastolic flow of the heart.This paper based on hemodynamics, attempts to provide a reasonable simulation and explanation of the relationship between atherosclerosis and pulse wave that to enable better diagnosis of arteriosclerosis in the application of pulse wave. Therefore, we introduced unit compliance which means arterial compliance per unit length. It is a bridge which on one hand make atherosclerosis equivalent to the reducing of the unit compliance, on the other hand unite the Windkessel model theory which describes the general characteristics of the vascular system and the one-dimensional transmission line theory which describes the instantaneous changes of blood pressure and flow.First, the paper discusses the relationship among reflection coefficient, blood pressure and vascular resistance in different frequencies of the pulse wave. Then, by those relations, the change of the pulse wave propagation and reflection is discussed, when the unit compliance changes in different parts of atherosclerosis in the single tube and vascular bifurcation, especially the change of reflection coefficient and blood pressure. And next, the result will be used in non-invasive arteriosclerosis detection. It discusses the effectiveness, advantages and disadvantages of the various methods of detecting atherosclerosis by pulse wave, which is the theoretical foundation of the apparatus which can detect atherosclerosis non-invasively. At the last part of the paper, it is the direction of future research and some problems to be solved in the future.However, this theoretical analysis and simulation results is not very accordance with experimental result. The main reason is that in the Windkessel model theory and one-dimensional transmission line theory, there are some simplifications and neglects of the research objects. In addition, there are deficiencies of the macro-arterial hemodynamics for describing the complicated system of the human body. These require further research, and looking for new ways to study and explore.